Posted on 12/31/15, 4:26 PM

Simple Cheap MMIC Preamps
Posted by Tom - KV2X

Quoting W1GHZ: "At Microwave Update 2013, WA5VJB was selling LNA kits at a reasonable price – the
kit consisted of a MMIC and a PC board. The PCB was marked G4DDK/G8EMY/VJB, two guyswho know about LNA design, so I bought one to give it a try. The MMIC is a Minicircuits PGA-103. The datasheet shows NF under 1 dB from 50 MHz up to 2 GHz. I put the kit together and fired it up – the Noise Figure is under 1 dB at 144, 432, and 1296 MHz, all with no tuning. Gain is 22.5 dB at 144 MHz, 20 dB at 432 MHz, and 12 dB at 1296 MHz. Not bad for a $1.99" See http://www.w1ghz.org/small_proj/Simple_Cheap_MMIC_Preamps.pdf for more details
device!

Posted on 01/02/16, 9:40 AM

Re: Simple Cheap MMIC Preamps
Posted by David--AB2YI

My problem with LNA is switching them in and out--finding low cost, compact relays for mast mount bias-T. Had wondered about using $29 ebay attenuator board (transverters-store) with 3 relays (Axiom 1m06) with mod to switch in LNA on RX. Board bypasses 100w on 28 mHz, but what power at 144, 432? Anyone with ideas, suggestions to put LNA to practical use?

Posted on 01/03/16, 10:03 AM

Re: Simple Cheap MMIC Preamps
Posted by Dana VE3DS

You should use some filtering if you are in an urban area I think...otherwise the device will see the whole spectrum. PGA-103's are pretty nice devices.

Posted on 01/03/16, 11:08 AM

Re: Simple Cheap MMIC Preamps
Posted by Tom - KV2X

I wonder if the Altoids Tin filters would be good enough?

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